There are many constructions which comprise a movable structure which is mounted on, and movable with respect to, a fixed structure. Springs and gas cylinders are conventionally used for displacing the movable structure in one direction with respect to the fixed structure after a latch is released. The potential energy of the spring or gas cylinder is expended during this movement. When the movable structure is manually displaced in the opposite direction with respect to the fixed structure, the spring is re-tensioned or the gas in the cylinder is recompressed. This provides the potential energy for the next movement of the movable structure.
The present invention provides a device which includes a spring, the device being for shifting a movable structure with respect to a fixed structure.